The present invention relates to an emergency ignition system for motor vehicles, and particularly to such a system for providing an alternative source of high-voltage pulses to the vehicle distributor in the event of a failure of the vehicle ignition system itself to provide such pulses.
The failure of a motor vehicle to start is frequently due to a malfunction in the ignition system of the vehicle preventing it from supplying the necessary high-voltage pulses to the distributor, which pulses are distributed by the distributor to the spark plugs in the cylinders of the vehicle engine. It has been proposed to provide, for use in such cases, an emergency ignition system, which includes a high-voltage coil having an input circuit connectible to the vehicle battery and an output circuit connectible to the vehicle distributor for supplying the high-voltage pulses thereto. In one known system, the input circuit to the high-voltage coil includes an oscillator generating periodic pulses, and a switch (e.g., a power transistor switch) controlled by the oscillator for periodically interrupting the input circuit to the coil and thereby causing the coil to generate high-voltage pulses to be applied to the vehicle distributor. In this known system, the oscillator is directly connected to the vehicle battery through a manual on/off switch, such that the oscillator immediately begins to oscillate upon closing the manual switch.